Specimen feed for a microtome

ABSTRACT

A manually positionable cam surface mounted on the frame of a microtome is used to control the amount of rotation of a single direction clutch for driving a feed screw to advance a tissue specimen toward a knife between the cutting strokes of the microtome.

United States Patent Shatzel, deceased Dec. 16, 1975 [5 SPECIMEN FEED FOR A MICROTOME 2,155,523 4/1939 Bausch et al. 83/9155 x 4 d1 74 5 l R [75] Inventor Norman shatzel deceased late 10/322 E/I c CSr mick et al 83/9 15 5 X of wllllamsvlll, by Mary 3,293,972 12/1966 Burkhardt et al 83/9155 x Shatzel, administratrix [73] Asslgnee: i Corporation Primary Examiner-Frank T. Yost ou n Assistant ExaminerW. D. Bray [22] Filed: Dec. 2, 1974 Attorney, Agent, or Firm-Alan H. Spencer; William [21] pp NO: 528,958 C. Nealon; H. R. Berkenstock, Jr.

[52] US. Cl 83/718; 74/1255; 74/571 R; 7

83/414; 83/425; 83/9155 [5 1 ABSTRACT [Sl] Int. Cl. GOIN 1/06 A manuan y pos1t1onable cam surface mounted on the [58] new of Search 83/412 717, 7181 frame of a microtome is used to control the amount of 83/9155 425; 74/1255 571 R rotation of a single direction clutch for driving a feed screw to advance a tissue specimen toward a knife be- [56] References and tween the cutting strokes of the microtome. UNITED STATES PATENTS 1,026,280 5/1912 On 83/915.5-X 2 Claims, 8 Drawing Figures r 2% 26 l T l 27 g 1 2 k 2 I 15 l I US. Patent Dec. 16,1975 Sheet10f4 3,926,085

Fig 1 US. Patent Dec. 16, 1975 Sheet 2 of 4 U.S. Patent Dec. 16, 1975 Sheet40f4 3,926,085

SPECIMEN FEED FOR A MICROTOME BACKGROUND OF THE INVENTION This invention relates to microtomes and in particular to a feed device for advancing the specimen toward the knife between cutting strokes of the microtome.

Conventional microtomes frequently utilize a paw and gear or ratchet type of mechanism to advance the specimen toward the knife between each cutting stroke of the microtome. Adjustment of such mechanism is limited to multiples of the smallest increment available as a result of tube spacing and the like.

SUMMARY OF THE INVENTION AND BRIEF DESCRIPTION OF THE DRAWINGS The present invention is directed to a microtome utilizing a single direction clutch to transmit motion to feed screw for advancing a specimen toward the knife between cutting strokes and a manually positionable cam for controlling the amount of motion of the feed screw to provide an infinitely adjustable selection of specimen thickness. I t

FIG. 1 is a side view of a microtome;

FIG. 2 is a front view, partly in section, of the microtome;

FIG. 3 is a top view, partly in section, of the microtome showing the specimen advance mechanism and single direction clutch;

FIG. 4 is an enlarged back view of the actuating finger and cam surface controlling the amount of specimen feed with the carriage approaching the limit of the return stroke;

FIG. 5 is another enlarged back view of the actuating finger and cam surface with the carriage at the limit of the return stroke;

FIG. 6 is an enlarged view of the fast advance hand wheel and connection to the single direction clutch shown partially in cross-section;

FIG. 7 is an enlarged front view of the disengagement mechanism for rapid advance and withdrawal of the specimen arm; and

FIG. 8 is a partial enlarged front view of the disengagement mechanism.

DETAILED DESCRIPTION OF THE DRAWINGS AND THE PREFERRED EMBODIMENT Referring to FIG. 1, a base 1 has a housing 2 and cover 3. The base 1 supports holder 4 which carries knife 5 secured by thumb screw 6. A specimen (not shown) is held in specimen arm 7 by clamp screw 8. Manual rotation of crank 9 using knob 10 causes the specimen arm 7 to move in a reciprocal path as shown by the double ended arrow. Hand wheel 11 is provided to rapidly advance or withdraw the specimen from the vicinity of knife 5. 5

In FIG. 2, base 1 has support with carriage l3 slideably mounted thereon. Carriage 13 has an elongated groove 14 adapted to slideably position dovetail portion 15 of specimen arm 7. Rotary motion of crank 10 istransrnitted to carriage 13 by means of eccentric 16 mounted on drivewheel 17 and carried by shaft 18 which is driven in turn by crank 9.

In FIG. 3 a top view of the microtome is shown partially sectioned along line 33. A disc 19 having cam surface 20 is carried by shaft 21 which is manually rotatable through knob 22. On the return stroke of specimen arm 7, carriage 13 moves up on support 12 in a direction toward shaft 21. As carriage 13 approaches the limit of the return stroke, finger 23 contacts cam surface 20 causing finger 23 mounted on single direction clutch 24 to rotate until the carriage reaches the limit of the return stroke. Rotation of the single direction clutch 24 is transmitted to shaft 25 rotatably mounted on slide 13. Shaft 25 has threaded portion 26 engaging a complimentary threaded bore 27 in the dovetail portion 15 of specimen arm 7, which converts the rota tional motion of shaft 25 to longitude motion of specimen arm 7.

FIG. 4 shows an enlarged back view of the portion of support 12 carrying disc 19 and cam surface 20. Carriage 13 is approaching the limit of the reciprocal path on the return stroke and finger 23 is almost in contact with cam surface 20.

FIG. 5 is another enlarged back view of the portion of the support 12 with carriage 13 at the extreme limit of the reciprocal path of the return stroke. As carriage l3 continues toward the limit of the reciprocal path on the return stroke while moving from the position of FIG. 4 to that shown in FIG. 5, finger 23 contacts cam surface 20 thereby rotating single direction clutch 24. The rotational movement is transmitted to shaft 25 until the limit of the reciprocal path is reached and movement of finger 23 stops. When the carriage reverses its direction in the cutting stroke direction of the reciprocal path, finger 23 returns to its normal position as shown in FIG. 4 due to the biasing action of spring 28, which has one end fastenen to carriage l3 and the other end to finger 23. The return of finger 23 to its normal position as shown in FIG. 4 does not transmit rotary motion to shaft 25 because the mechanism (not shown) of single direction clutch 24 only transmits rotary motion in one direction, i.e. the feed direction.

The distance specimen arm 7 is advanced toward knife 5 is controlled by the manually preselected rotational position of disc 19 and cam surface 20. The continuous curved surface 20 of disc 19 enables one to preselect an incrementally variable cutting advance within the limits of the range provided, since the arc through which single direction clutch 24 and shaft 25 are rotated controls the amount of specimen feed toward knife 5 produced by threaded portion 26 on shaft 25.

Rapid advance of specimen arm 7 toward knife 5 or retraction of the specimen arm 7 from the vacinity of knife 5 is accomplished by rotation of handwheel 11 mounted on shaft 25. Handwheel 11 has means to provide disengagement from single direction clutch 24 when rotation to withdraw the specimen is desired. The means for disengagement of handwheel 11 from single direction clutch 24 includes a bushing 38 mounted near the periphery of handwheel 11 carrying knob 29 with a slideable pin 30 passing through the center of knob 29 and bushing 38. Pin 30 is of sufficient length to extend beyond knob 29 and has a collar 32 mounted thereon to provide a normally biased position as shown in FIG. 7 in cooperation with spring 33, pin 30, has a tapered end extending through handwheel 11 which, when pressed, rotates extension 34 of lock 35 pivoted on screw 36. Spring 37 normally biases 35 into one of a plurality of notches 39 (one shown) located in the peripheral portion of clutch 24. As shown in FIG. 8 pin 30 is depressed toward handwheel 11, lock 35 is removed from notch 39 as shown in FIG. 8 and handwheel 1 1 is free to be rapidly rotated in a direction against the feed without interference from the single direction clutch. When the feed mechanism is operating during the re- 3 turn stroke of specimen arm 7, rotation, of single direction clutch 24 produced by contact of cam surface against finger 23, is transmitted to shaft through lock 35 engaging single direction clutch 24.

Since the single direction clutch 24 permits shaft 25 to be freely rotated in the direction producing longitudinal motion of the specimen arm 7 toward knife 5, it is unnecessary to disengage the single direction clutch before rapidly advancing the specimen.

The foregoing description of an embodiment of this invention is given by way of illustration and not of limitation. The concept and scope of the invention are limited only by the following claims and equivalence thereof which may occur to others skilled in the art.

What is claimed is:

l. A microtome having a base, a support extending from said base, a carriage slideably mounted on said support, a manually operable drive means to move said carriage in a reciprocating path along said support, a manually positionable actuator on said support positionable along an axis parallel to the reciprocating path, a slideable specimen holder arm extending from said carriage in a direction generally perpendicular to the reciprocating path, means for holding a specimen in the distal end of said arm, a knife adjustably mounted on said base and positioned to cut said specimen as said carriage travels along said reciprocating path in one direction, an incremental feed means connecting said arm and said carriage, said feed means including a shaft mounted on said carriage, one end of said shaft being threaded, means mounted in said arm to engage the threads on said shaft, a clutch mounted on the other end of said shaft, said clutch being adapted to rotate said shaft in a single direction to advance the specimen toward said knife, a finger mounted to and extending from said clutch, said finger being adapted to engage said actuator as said carriage travels along said reciprocating path in the other direction to rotate said clutch and shaft through a small arc thereby providing an incremental feed of said specimen toward the knife between cuts.

2. The microtomes of claim 1 wherein said manually positionable actuator includes a shaft mounted on said support, a disc mounted on said shaft, said disc having a cam positioned to engage said finger as said carriage travels along said reciprocating path in the other direction, and manual means to selectively rotate said disc to provide incremental adjustment of the cam surface to vary the amount of are said shaft is rotated and the resultant feed of said specimen toward said knife. 

1. A microtome having a base, a support extending from said base, a carriage slideably mounted on said support, a manually operable drive means to move said carriage in a reciprocating path along said support, a manually positionable actuator on said support positionable along an axis parallel to the reciprocating path, a slideable specimen holder arm extending from said carriage in a direction generally perpendicular to the reciprocating path, means for holding a specimen in the distal end of said arm, a knife adjustably mounted on said base and positioned to cut said specimen as said carriage travels along said reciprocating path in one direction, an incremental feed means connecting said arm and said carriage, said feed means including a shaft mounted on said carriage, one end of said shaft being threaded, means mounted in said arm to engage the threads on said shaft, a clutch mounted on the other end of said shaft, said clutch being adapted to rotate said shaft in a single direction to advance the specimen toward said knife, a finger mounted to and extending from said clutch, said finger being adapted to engage said actuator as said carriage travels along said reciprocating path in the other direction to rotate said clutch and shaft through a small arc thereby providing an incremental feed of said specimen toward the knife between cuts.
 2. The microtomes of claim 1 wherein said manually positionable actuator includes a shaft mounted on said support, a disc mounted on said shaft, said disc having a cam positioned to engage said finger as said carriage travels along said reciprocating path in the other direction, and manual means to selectively rotate said disc to provide incremental adjustment of the cam surface to vary the amount of arc said shaft is rotated and the resultant feed of said specimen toward said knife. 